Method and equipment for making jewelry products, in particular tennis-type bracelets

ABSTRACT

A method of making tennis bracelets includes coupling together collet elements ( 2 ) in a repetitive series, wherein an L-shaped lateral appendage ( 3 ) of a collet element is inserted into a through hole ( 6 ) of an immediately adjacent collet element and then bent against a face ( 7 ) of the collet element to which it belongs. The collet elements are inserted according to the repetitive series into an assembly template ( 10 ) implemented as a self-supporting unit provided with fasteners ( 16 ) for fastening the unit to first and second carriage supports ( 22, 36 ) of first and second machines ( 18, 19 ), which cause the assembly template to translate under a die block ( 26 ) of a press device ( 24 ) of the first machine. The lateral appendages ( 3 ) of the collet elements are bent in succession under a laser welding head ( 38 ) of the second machine, for welding the appendages ( 3 ) to their respective collet elements.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method and an equipment for quickly and efficiently assembling link-type jewellery products, e.g. consisting of a link chain structure, such as bracelets/armlets of the type commonly known as TENNIS.

PRIOR ART

Italian patent no. 1383693 describes a product of jewellery or costume jewellery, or the like, made up of a link chain structure forming a bracelet. Such a link chain structure is formed by a plurality of collet elements, arranged side by side according to a repetitive series that develops longitudinally, wherein the collet elements are linked to each other.

Such a type of bracelets, known as tennis, permits the insertion of an ornamental stone, e.g. a precious or semi-precious one, on each collet element, which stones seem to be, in the finished bracelet, joined together without solution of continuity.

Said Italian patent teaches to make such bracelets by means of collet elements internally delimiting a central cavity or hole and integrally provided, as one piece, with an L-shaped lateral appendage that is inserted into the central cavity of an immediately adjacent collet element, in a downward direction, and then bent against the bottom of the collet element the appendage of which has been folded, thereby obtaining a hinge connection between each pair of adjacent collet elements.

Such operations are carried out manually by a skilled goldsmith, by inserting and locking the collet elements in a vice, which also allows for proper alignment thereof, by bending the L-shaped appendage with a tool such as pliers, a screwdriver or the like, collet by collet, and then by definitively securing the folded appendages to the bottom of the respective collet elements, which is provided with a suitable receiving seat, by welding, e.g. brazing.

Although it has made it possible to considerably speed up and simplify the operations necessary for assembling a link chain bracelet, such a system is nevertheless still complex and relatively slow, resulting in relatively high costs, which costs may be acceptable for jewellery products but are much less acceptable for costume jewellery products, where the collet elements are made of relatively cheap metal alloys and, most importantly, the ornamental stones are simple glass or artificial stones, e.g. zircons.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a method and an equipment for making link chain jewellery or costume jewellery products, e.g. bracelets, in a simple, fast and relatively inexpensive manner, which can also be executed/operated by unskilled personnel.

Therefore, the invention provides a method and an equipment for making link chain jewellery or costume jewellery products such as, for example, tennis-type bracelets, having the features set out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will become more apparent from the following description of a non-limiting embodiment thereof as shown in the annexed drawings, wherein:

FIG. 1 schematically shows the equipment of the invention, including a first machine and a second machine, the latter being illustrated only in a schematic manner;

FIG. 2 schematically shows, in a larger scale, the second machine included in the equipment of FIG. 1, with some parts removed for a better understanding;

FIGS. 3 and 4 respectively show a three-quarter perspective view from below of a component of the equipment of FIG. 1 and a sectional view along a plane IV-IV of the component of FIG. 3;

FIG. 5 shows an exploded perspective view of the first machine of the equipment of FIG. 1;

FIG. 6 schematically shows, in a larger scale, one type of operation that can be carried out with the equipment of the invention; and

FIG. 7 shows an exploded perspective view of a second component of the equipment of FIG. 1 and, in a larger scale, of a detail thereof.

DETAILED DESCRIPTION

With reference to FIG. 1, numeral 1 designates as a whole an equipment for making link chain jewellery or costume jewellery products, e.g. tennis-type bracelets. In particular, as will be explained below, equipment 1 is useful for manufacturing in a partially automated and simplified manner bracelets and other link chain products as described in Italian patent no. 1383693, the contents of which have been incorporated herein for easy reference.

With reference to FIG. 6, in this type of link chain articles/products, a plurality of identical collet elements 2 must be arranged side by side according to a repetitive series that develops longitudinally, to be linked to each other by means of an L-shaped lateral appendage 3, which protrudes in a cantilever fashion from a same first face 4 and on a same side 5 of each collet element 2, extending past, and thus projecting from, a second face 7 of collet element 2 opposite to face 4. Appendage 3 protruding in a cantilever fashion from (relative to) face 7 is inserted through a central hole 6 of another collet element 2 immediately adjacent thereto, and is then bent against the second face 7 of the same collet element 2 to which appendage 3 in question belongs.

On the side of face 4 opposite to L-shaped appendage 3, respective tips or “legs” 8 of collet element 2 protrude in the same axial direction as that of appendage 3 (relative to hole 6), configured for receiving and interlocking with, when in use, an ornamental stone, which is known and will not be illustrated herein for simplicity.

Hole 6 is generally a round through hole and is anyway symmetrical with respect to an axis A parallel to the direction of projection of appendage 3 and tips 8.

Each collet element 2 is delimited, laterally relative to side 5, by a pair of flat side surfaces 9, arranged substantially perpendicular to side 5, which is also defined by a flat surface.

By connecting multiple collet elements 2 together by bending L-shaped appendages 3, one can obtain any link chain product, such as a bracelet, a necklace, a pendant, etc. This description will refer to the making of a bracelet, but it is clear that the following teachings are also applicable to any other link chain jewellery/costume jewellery product.

Equipment 1 according to the invention comprises (FIGS. 1, 2, 6 and 7) an assembly template 10 for collet elements 2, configured to receive collet elements 2 coupled together two by two according to the above-mentioned repetitive longitudinal series within a channel 11 of adjustable length, to form at the end of the processing, as will be explained hereinafter, a semi-finished product 12 (FIGS. 6 and 7).

Channel 11 is delimited by two jaws 13 b, 13 c of assembly template 10.

Jaws 13 b, c are defined, in the illustrated example, by straight parallelepiped plate elements, and are mounted relatively mobile with respect to each other, one towards the other, e.g. by means of one or more screws (which are known and therefore not illustrated herein for simplicity) that can be coupled to holes 14 (FIG. 7), so as to be able to clamp, on opposite sides, a plurality of collet elements 2 arranged in channel 11 according to the above-mentioned repetitive series by acting against opposite side surfaces 9.

At least one of jaws 13, in the illustrated example jaw 13 b, comprises a surface plate 15 (FIG. 7) configured to receive, resting thereon, collet elements 2 from the side opposite to face 7 from which L-shaped appendage 3 protrudes in a cantilever fashion, i.e. from the side of face 4 and tips 8.

According to a first feature of the invention, assembly template 10 is made as a self-supporting unit provided with fastening means 16 for fastening it to a support; fastening means 16 consist of, in the illustrated example, ears 16 formed integrally with the opposite ends of jaw 13 b, projecting longitudinally therefrom, and provided with fastening holes 17 (FIG. 7) for suitable screws, which are known and therefore not illustrated herein for simplicity. It is clear that any other fastening means other than ears 16 may also be used; for example, template 10 may be provided with suitable seats for inserting it with a snap action into a support.

According to an important feature of the invention, surface plate 15 is not flat (FIG. 7), since it is provided with a toothing 150 comprising a plurality of teeth 151 spaced apart, in a longitudinal development direction of jaws 13 b, c, by a pitch or interval P. Teeth 151 are present in a number equal to (or possibly larger than) the number of collets 2 to be received in channel 11, and are configured for coupling each between tips or legs 8 of a respective collet 2 arranged with face 4 towards toothing 150 and side surfaces 9 parallel to teeth 151.

According to the invention, equipment 1 also comprises at least one first machine 18 and at least one second machine 19, which are schematically illustrated together in Figure and intended for sequential operation, but are not necessarily close to each other in actual use.

Machine 18 is schematically illustrated in the detail of FIG. 1 and in an exploded configuration in FIG. 5 for a better understanding.

Machine 18 is used for assembling together a plurality of collet elements 2 and obtaining a semifinished link chain product 12, in which collet elements 2 have already been linked together.

Machine 18 comprises: a first stationary pedestal 20; respective first guides 21, which in the preferred embodiment are straight, guides 21 being integrally carried by the first pedestal 20; a first carriage support 22, movable along the first guides 21 in a sliding manner with a reciprocating straight motion along a first path T1 having a pre-set length and configured to receive integrally, yet in a removable manner, assembly template 10; first adjustable actuators 23 for moving the first carriage support 22 to and fro along the first guides 21; and a press device 24 supported by the first pedestal 20 at a first end 25 of the first path T1, which end 25 faces towards a first end-of-stroke position of the first carriage support 22, shown in FIGS. 1 and 5, wherein assembly template 10 lies lower than, but not under, press device 24.

Press device 24 is provided with an interchangeable die block 26 and stop means 27 for stopping die block 26 in a position in which it is adapted to interfere with lateral appendages 3.

In fact, die block 26 is configured to bend in succession, one at a time, lateral appendages 3 of collet elements 2 pre-coupled according to the above-mentioned repetitive series, as a consequence of the transit of carriage support 22 under die block 26.

For this purpose, press device 24 comprises: a pair of support feet 28 integrally fixed to the first pedestal 20 on both opposite sides of the first guides 21, which first guides 21 are arranged between support feet 28; a plurality of guiding columns 29 integrally fixed to support feet 28, on top of the same, at a bottom end 30 thereof (FIG. 5); a first plate element 31 integrally fixed to a top end of guiding columns 29, opposite to end 30; a second plate element 32 that slidably engages guiding columns 29 and integrally carries at the bottom, in a removable manner, die block 26; and motor means 33 integrally carried by the first plate element 31 and adapted to move the second plate element 32 along guiding columns 29, so as to selectively move it closer to or away from support feet 28.

Stop means 27 of the die block consist of respective upper ends of support feet 28 (FIG. 5).

Motor means 33 are configured to keep the second plate element 32 locked in abutment against upper ends 27 of support feet 28, so as to arrange die block 26 in a first operating position, shown in FIG. 1, in which it is adapted to interfere with lateral appendages 3 of collet elements 2.

Motor means 33 are also configured to selectively move die block 26 into a second operating position, not shown herein for simplicity, in which die block 26 is farther away from carriage support 22 and the second plate element 32 is in proximity to or against the first plate element 31.

In the illustrated example, motor means 33 are of a known hydraulic or pneumatic type, but may of course also be of the electromechanical type.

According to a further feature of the invention, the second machine 19 (FIG. 2) comprises: a second stationary pedestal 34; respective second straight guides 35 integrally carried by the second pedestal 34; a second carriage support 36, movable along the second guides 35 in a sliding manner with a reciprocating straight motion along a second path T2 having a pre-set length and configured to receive integrally, yet in a removable manner, assembly template 10; second adjustable actuators 37 for moving the second carriage support 36 along the second guides 35 for fractions of motion equal to a centre-to-centre distance or pitch P (FIG. 6) between collet elements 2 coupled two by two according to the above-mentioned repetitive series; and a welding head 38 of any known kind, supported by the second pedestal 34 above the second carriage support 36 and at a first end 39 of the second path T2 facing towards a first end-of-stroke position of the second carriage support 36, shown in FIG. 2, wherein the assembly template 10 lies lower than, but not under, welding head 38.

Collets 2 are assembled with a constant pitch P, due to the fact that they are inserted, one by one, on a respective tooth 151.

Welding head 38 faces towards the second guides 35 and is configured to weld, one at a time, lateral appendages 3 of collet elements 2 coupled according to the above-mentioned repetitive series, each lateral appendage 3 to respective collet element 2 to which it belongs, as the second carriage support 36 carries along collet elements 2 under welding head 38.

According to a preferred embodiment of the invention, welding head 38 is a laser welding machine; this selection has proved to be fully satisfactory, in actual use, for automating the welding process, since it has surprisingly demonstrated to be able to effectively weld lateral appendages 3 to the respective collet elements 2 and against face 7 (preferably provided with suitable receiving seats, not shown herein for simplicity) without requiring any filler metal and without resorting to traditional brazing techniques.

For safety reasons, however, laser welding head 38 must be protected; therefore, machine 19 comprises also a cover 119 (FIG. 1), which covers not only laser head 38, but also carriage support 37 and its driving means; such cover 119 has been removed in FIG. 2, but the latter shows an inspection window 120, which, when in use, looks exactly over laser head 38.

According to the invention, fastening means 16 for fastening assembly template 10 are configured to integrally, and yet removably, couple assembly template 10 to, selectively, the first carriage support 22 and the second carriage support 36. For example, when using a snap-action coupling (which variant is not shown herein for simplicity), stop means 16 consist of seats intended to receive stop ferrules carried by carriage supports 22, 36, with respective guides into which the opposite ends of template 10 are slidably inserted.

In fact, the first machine 18 and the second machine 19 can be used in sequence, so that the at least one second machine 19 receives a first assembly template 10 from the at least one first machine 18 after the bending of lateral appendages 3, while the at least one first machine 18 is free to receive a second assembly template 10 different from the first one (not shown for simplicity), provided with collet elements 2 whose lateral appendages 3 are still to be bent. Depending on the working speed attainable by each machine 18 and 19, an equipment 1 may include only one machine 18 and more (two) machines 19, or vice versa, so as to avoid any downtime. For the same reason, each machine 18, 19 may be configured, according to a variant not shown herein, to receive two different templates 10 in succession for doubled productivity, as will be explained hereinafter.

The first and second guides 21, 35 of each first and second machine 18, 19 are defined by opposite longitudinal sides of, respectively, first and second H-beams, respectively designated as 40 and 41, which are integrally fixed to the respective pedestals 20, 34.

At least the first carriage support 22 (preferably both carriage supports 22 and 36—the same reference numerals of the components of carriage support 22 have also been used, for simplicity, for carriage support 36) comprises a rigid frame structure 42 H-shaped in a direction parallel to the first guides 21 (guides 35 for carriage support 36) and comprising a first pair of legs 43 that engage the first and, respectively, the second guides 21 and 35, and a second pair of legs 44 configured to support assembly template 10 at respective opposite ends of the latter, which in the non-limiting example illustrated herein are provided with ears 16 and are, for carriage support 22 only, substantially flush with stop means 27 of die block 26.

With reference to FIGS. 3 and 4, die block 26 consists of a metal block 26 b, in the illustrated example having a parallelepiped shape, provided at the bottom with a longitudinal groove 45 oriented parallel to the first guides 21 and configured to receive, in a through manner, an upper edge 46 of jaws 13 b, 13 c of assembly template 10.

Edges 46 of the pair of jaws 13 (13 b, 13 c) delimit channel 11, which is configured in such a way that at least lateral appendages 3 of collet elements 2 protrude in a cantilever fashion from the same.

Groove 45 has a first open end 47 facing the side of the first end 25 of the first path T1 and a second open end 48 opposite to the first one and facing a second end 49 of the first path T1 facing towards a second end-of-stroke position (not shown herein for simplicity) of the first carriage support 22, in which assembly template 10 has fully passed under press device 24.

Groove 45 is centrally equipped with a longitudinal rib 50 extending from the second end 48 of groove 45 towards the first end 47 of groove 45, without however occupying an end stretch 51 thereof immediately adjacent to the first end 47.

Rib 50 is delimited towards the first end 47 of groove 45 by a first inclined plane 52 that extends from a flat top surface 53 of longitudinal rib 50 towards a bottom wall 54 of longitudinal groove 45, on the side of the first end 47 of the latter.

Longitudinal groove 45 is internally provided with, at end stretch 51, a pair of lateral projections 55 delimiting a channel 56 in between, aligned with longitudinal rib 50 and configured to slidably receive, inside of it, lateral appendages 3.

Projections 55 are delimited towards the first end 47 by respective second inclined planes 57 oriented like the first inclined plane 52.

Preferably, also the mouth of end 47 is provided on both of its opposite lateral flanks with inclined guiding surfaces 58, configured to ensure that assembly template 10 will enter groove 45 and slide therein perfectly aligned therewith.

The first adjustable actuators 23 consist of: a worm screw 59 carried idle by the first pedestal 20 under the first carriage support 22 and for at least the entire length of the first path T1; a nut 60, through which worm screw 59 engages, integrally carried by the first carriage support 22, preferably on the side of the first end 25 of the first path T1; a gear device 61 for rotating worm screw 59, carried by the first pedestal 20; and a driving wheel 62, preferably provided with a handle for manual operation, for actuating gear device 61. Of course, wheel 62 may be replaced with a suitable known motor.

Gear device 61, according to one aspect of the invention, is configured in such a way that its transmission ratio can be changed, if necessary, in a simple and quick manner; for example, it may comprise a gearbox, or it may be configured to allow for quick replacement of one or more gears. In this way it is possible to adjust the revolution speed of worm screw 59 and, as a consequence, the translation speed of carriage support 22. Of course, gear device 61 is also configured to allow reversing the motion of carriage support 22, so that, when the latter reaches the second end-of-stroke position, it can be brought back into the first end-of-stroke position by reversing the rotation of worm screw 59. The return stroke can be used for bending a second series of collets 2, in the aforementioned case wherein carriage support 22 receives in succession two templates 10 mounted in opposite ways and die block 26 has a symmetric configuration.

The second adjustable actuators 37 consist of: a worm screw 63 carried idle by the second pedestal 34 under the second carriage support 36 for at least the entire length of the second path T2; a nut 64, through which the worm screw 63 engages, integrally carried by the second carriage support 36, preferably on the side of the first end 39 of the second path T2; and an adjustable-speed, reversible stepper motor 65 for rotating worm screw 63. In this case as well, carriage support 36 and worm screw 63 are so designed as to be able to bring carriage support 36 into a second end-of-stroke position (not shown), in which the whole assembly template 10 has passed under welding head 38. Stepper motor 65 is controlled by a programmable control unit 650, e.g. consisting of a PLC, carried by pedestal 34.

In the light of the above description, it can be inferred that the invention also relates to a method for making link chain jewellery or costume jewellery products, e.g. tennis-type bracelets, wherein a plurality of collet elements 2 identical to one another are arranged side by side according to a repetitive series that develops longitudinally, so as to be linked together by means of an L-shaped lateral appendage 3 protruding in a cantilever fashion from a same face 7 and on a same side 5 of each collet element 2, which is first inserted through a central hole 6 of another collet element 2 immediately adjacent thereto and then bent against face 7 of collet element 2 to which the appendage belongs.

The method of the invention comprising the steps of:

a)—making an assembly template 10 for collet elements 2, formed by a pair of relatively mobile jaws 13 b, 13 c delimiting in between a channel 11 of adjustable width, a bottom wall of which is defined by a surface plate 15 integrally carried by at least one of jaws 13; assembly template 10 being implemented as a self-supporting unit provided with fastening means 16 for fastening it to a support, and surface plate 15 being provided with a toothing 150 having a pitch P;

b)—inserting collet elements 2, one by one, into said channel 11, coupling them according to said repetitive longitudinal series, said collet elements 2 resting on surface plate 15 on the side opposite to face 7 from which L-shaped appendage 3 protrudes in a cantilever fashion, and inserting the latter into central hole 6 of an immediately adjacent collet element 2, taking care of coupling each collet element 2 with a respective tooth 151 of toothing 150;

c)—connecting assembly template 10 in an integral, and yet removable, manner to a first carriage support 22 of a first machine 18 provided with a press device 24 including an interchangeable die block 26 and stop means 27 for stopping die block 26 in a position in which it is adapted to interfere with lateral appendages 3 of collet elements 2;

d)—translating said assembly template 10 under press device 24 throughout its length and along a first path T1 under die block 26 of press device 24, so as to bend in succession, one at a time, lateral appendages 3 of collet elements 2 coupled according to the above-mentioned repetitive series, as a consequence of the transit of carriage support 22 under die block 26;

e)—transferring assembly template 10, after the bending of lateral appendages 3 of all collet elements 2, onto a second machine 19, connecting assembly template 10 in an integral, and yet removable, manner to a second carriage support 36 of the second machine, which is provided with a laser welding head 38;

f)—translating assembly template 10 under welding head throughout its length and along a second path T2, by moving the second carriage support 36 under welding head 38;

g)—stopping the second carriage support 36 under welding head 38 after each one of a plurality of fractions of motion along the second path T2 equal to a centre-to-centre distance or pitch P between collet elements 2 coupled according to the above-mentioned repetitive series, and activating welding head 38 in order to weld each lateral appendage 3, already bent, to its own collet element 2;

h) removing assembly template 10 and picking up a link chain product formed by said plurality of collet elements 2 now linked in a permanent manner, according to the above-mentioned repetitive series.

The bending of lateral appendages 3 occurs because of the linear transit of assembly template 10 under die block 26, and in particular because of the combined presence of rib 50, projections 55 and inclined planes 52 and 57 within longitudinal groove 45, which receives through it template with appendages 3 protruding upwards in a cantilever fashion, thus ensuring a perfect and correct bending, better than that obtainable manually, since it is sufficient that an operator turns driving wheel 62.

Therefore, all the objects of the inventions are achieved. 

1. An equipment for making link chain jewelry or costume jewelry products, wherein a plurality of collet elements identical to one another are arranged side by side according to a repetitive series that develops longitudinally, to be linked together by an L-shaped lateral appendage protruding in a cantilever fashion from a same face and on a same side of each collet element, which is first inserted through a central hole of another immediately adjacent collet element and then bent against the face of the collet element to which the appendage belongs; the equipment comprising an assembly template for the collet elements, configured to receive the collet elements coupled according to said repetitive longitudinal series within a channel of adjustable width delimited by two relatively mobile jaws of the assembly template, at least one of the jaws comprises a surface plate configured to receive, resting the surface plate, said collet elements from the side opposite to the face from which the L-shaped appendage protrudes in a cantilever fashion; i) wherein the assembly template comprises a self-supporting unit provided with a fastener for fastening the assembly template to a support; ii) at least one first machine, comprising: a first stationary pedestal; respective first guides integrally carried by the first pedestal; a first carriage support, movable along the first guides in a sliding manner along a first path having a pre-set length and configured to receive integrally, yet in a removable manner, said assembly template; first adjustable actuators for moving the first carriage support along the first guides; and a press device supported by the first pedestal at a first end of the first path facing towards a first end-of stroke position of the first carriage support, wherein the assembly template lies lower than, but not under, the press device; the press device being provided with an interchangeable die block and a stop for stopping the die block in a position in which the die block is adapted to interfere with the lateral appendages, the die block being configured to bend in succession, one at a time, said lateral appendages of the collet elements coupled according to said repetitive series, as a consequence of the transit of the carriage support under the die block; iii) at least one second machine, comprising: a second stationary pedestal; respective second guides integrally carried by the second pedestal; a second carriage support, movable along the second guides in a sliding manner along a second path having a pre-set length and configured to receive integrally, yet in a removable manner, said assembly template; second adjustable actuators for moving the second carriage support along the second guides for fractions of motion equal to a centre-to-centre distance or pitch between said collet elements coupled according to said repetitive series; and a welding head supported by the second pedestal above the second carriage support and at a first end of the second path facing towards a first end-of-stroke position of the second carriage support, wherein the assembly template lies lower than, but not under, the welding head; the welding head facing towards the second guides and being configured to weld, one at a time, said lateral appendages of the collet elements coupled according to said repetitive series, each lateral appendage to the respective collet element to which each lateral appendage belongs, as the second carriage support carries along the collet elements under the welding head.
 2. The equipment according to claim 1, wherein the fastener for fastening the assembly template to a support is configured to integrally and removably couple the assembly template to, selectively, the first and second carriage supports.
 3. The equipment according to claim 1, wherein said first and second machines are usable in sequence, so that the at least one second machine receives a first assembly template from the at least one first machine after the bending of the lateral appendages has been carried out, while the at least one first machine is free to receive a second assembly template provided with collet elements having still to be bent lateral appendages.
 4. The equipment according to claim 1, wherein said first and second guides of each one of said first and second machines are defined by opposite longitudinal sides of, respectively, first and second H-beams integrally fixed to the respective first and second pedestals; at least said first carriage support comprising a rigid frame structure H-shaped in a direction parallel to the first guides and comprising a first pair of legs engaging said first guides and a second pair of legs configured to support said assembly template at respective opposite ends of the assembly template and substantially flush with said stop of the die block.
 5. The equipment according to claim 4, wherein the press device comprises: a pair of support feet integrally fixed to the first pedestal on both opposite sides of the first guides, wherein the first guides are arranged between said support feet; a plurality of guiding columns integrally fixed to the support feet, on top of the support feet, at a bottom end of the guiding columns; a first plate element integrally fixed to a top end of the guiding columns; a second plate element slidably engaging said guiding columns and carries, at the bottom, said die block; and a motor carried by the first plate element and adapted to move the second plate element along the guiding columns, to selectively move the second plate element closer to or away from the support feet; said stop of the die block comprising respective upper ends of the support feet, said motor being configured to keep said second plate element locked in abutment against the upper ends of the support feet, to arrange the die block in a first operating position, in which the die block is adapted to interfere with the lateral appendages of the collet elements; and to selectively move the die block into a second operating position, in which the die block is farther away from the carriage support and the second plate element is in proximity to or against the first plate element.
 6. The equipment according to claim 5, wherein the die block comprises a metal block provided at the bottom with a longitudinal groove oriented parallel to the first guides and configured to receive, in a through manner, an upper edge of the jaws of the assembly template delimiting said channel and configured so that at least said lateral appendages of the collet elements protrude in a cantilever fashion from the collet elements; said groove having a first open end facing the side of the first end of the first path and a second open end opposite to the first one and facing a second end of the first path facing towards a second end-of-stroke position of the first carriage support, in which the assembly template has fully passed under the press device; said groove being centrally equipped with a longitudinal rib extending from the second end of the groove towards the first end of the groove; without occupying at least an end stretch of the groove immediately adjacent to the first end; said rib being delimited towards said first end by a first inclined plane extending from a flat top surface of the longitudinal rib towards a bottom wall of the longitudinal groove, on the side of the first end of the bottom wall; the longitudinal groove being internally provided with, at said end stretch of the first end of the longitudinal groove, a pair of lateral projections delimiting a channel in between the lateral projections, aligned with the longitudinal rib, and delimited towards the first end by respective second inclined planes oriented like the first inclined plane.
 7. The equipment according to claim 1, wherein said first adjustable actuators comprise: a worm screw carried idle by the first pedestal under the first carriage support for at least an entire length of the first path; a nut, through which the worm screw engages, carried by said first carriage support, on the side of the first end of the first path; a gear device for rotating the worm screw, carried by the first pedestal; and a driving wheel, provided with a handle for manual operation, for actuating the gear device; the gear device being configured so that a transmission ratio of the gear device is changeable.
 8. The equipment according to claim 1, wherein said second adjustable actuators comprise: a worm screw carried idle by the second pedestal under the second carriage support for at least an entire length of the second path; a nut, through which the worm screw engages, carried by said second carriage support, on the side of the first end of the second path; and an adjustable-speed stepper motor for rotating the worm screw, controlled by a programmable control unit.
 9. The equipment according to claim 1, wherein said welding head is a laser welding machine.
 10. A method for making link chain jewelry or costume jewelry products, wherein a plurality of collet elements identical to one another are arranged side by side according to a repetitive series that develops longitudinally, to be linked together by an L-shaped lateral appendage protruding in a cantilever fashion from a same face and on a same side of each collet element, the L-shaped lateral appendage is first inserted through a central hole of another immediately adjacent collet element and then bent against the face of the collet element to which the appendage belongs; the method comprising the steps of: a) making an assembly template for the collet elements, formed by a pair of relatively mobile jaws delimiting in between the jaws a channel of adjustable width, a bottom wall of the channel is defined by a surface plate integrally carried by at least one of the jaws; the assembly template comprising a self-supporting unit provided with a fastener for fastening the assembly template to a support; b) inserting the collet elements, one by one; into said channel, coupling the collet elements according to said repetitive longitudinal series, said collet elements resting on the surface plate on a side opposite to the face from which the L-shaped appendage protrudes in a cantilever fashion, and inserting the L-shaped appendage into the central hole of an immediately adjacent collet element; c) connecting the assembly template in an integral, yet removable, manner to a first carriage support of a first machine provided with a press device including an interchangeable die block and a stop for stopping the die block in a position in which the die block is adapted to interfere with the lateral appendages of the collet elements; d) translating said assembly template under the press device throughout a length of the assembly template and along a first path under the die block of the press device, to bend in succession, one at a time, said lateral appendages of the collet elements coupled according to said repetitive series, as a consequence of the transit of the carriage support under the die block; e) transferring the assembly template, after the bending of the lateral appendages of all the collet elements, onto a second machine, connecting the assembly template in an integral, yet removable, manner to a second carriage support of the second machine, the second machine being provided with a laser welding head; f) translating said assembly template under the welding head throughout the length of the assembly template and along a second path, by moving the second carriage support under the welding head; g) stopping the second carriage support under the welding head after each one of a plurality of fractions of motion along said second path equal to a centre-to-centre distance or pitch between said collet elements coupled according to said repetitive series, and activating the welding head to weld each lateral appendage, already bent, to an associated collet element; h) removing the assembly template and a link chain product formed by, said plurality of collet elements linked in a permanent manner according to said repetitive series. 